Hybrid Feedback Control Research Articles

Function Projective Synchronization of Complex Networks With Distributed Delays via Hybrid Feedback Control

Due to its applications, some types of synchronization of complex networks have been intensively investigated. In particular, as a more general type of synchronization, function projective synchronization (FPS) has been investigated for complex networks with time delay or with time-varying delay. In this paper, we investigate FPS of complex networks with distributed delays. It is proven that, FPS of such networks can be realized via hybrid feedback control. Finally, two numerical examples are provided to illustrate the effectiveness of the proposed method.

Control Barrier Functions for Multi-Agent Systems Under Conflicting Local Signal Temporal Logic Tasks

Motivated by the recent interest in cyber-physical and interconnected autonomous systems, we study the problem of dynamically coupled multi-agent systems under conflicting local signal temporal logic (STL) tasks. Each agent is assigned a local STL task regardless of the tasks that the other agents are assigned to. Such a task may be dependent, i.e., the satisfaction of the task may depend on the behavior of more than one agent, so that the satisfaction of the conjunction of all local tasks may be conflicting. We propose a hybrid feedback control strategy using time-varying control barrier functions. Our control strategy finds least violating solutions in the aforementioned conflicting situations based on a suitable robustness notion and by initiating collaboration among agents.

Function matrix projective synchronization of non-dissipatively coupled heterogeneous systems with different-dimensional nodes

This paper regards function matrix projective synchronization of two different non-dissipatively coupled complex dynamical networks for different dimensions and different nodes. In this kind of complex dynamical networks the internal delays are different from the coupled delays. By using Lyapunov stability theory, using mathematical induction, two different hybrid feedback controllers are built to realize the function matrix projective synchronization. Compared with the existing results, the coupling matrices do not need to be symmetric or diffuse. By giving a numerical simulation we explain the validity and appropriateness of our conclusion.

Trajectory Following of a Tethered Underwater Robot With Multiple Control Techniques

A three-dimensional hydrodynamics and control model to simulate a tethered underwater robot system is proposed. The fluid motion around the robot main body with control ducted propellers is governed by the Navier–Stokes equations, and multiple sliding mesh technique is applied for the numerical solution of the equations. The governing equation of umbilical cable is based on the Ablow and Schechter method. The six degrees-of-freedom equations of motion for underwater vehicle simulations are adopted to estimate the hydrodynamic performance of the underwater robot. In the model, a hybrid feed-forward and feedback control technique is applied to adjust the length of the umbilical cable, and the incremental proportional-integral-derivative (PID) control algorithm is adopted to regulate the rotating speeds of the ducted propellers. The numerical results indicate that the multiple control techniques applied in this paper are feasible and effective, and adjusting the length of the umbilical cable is largely responsible for the vertical trajectory control to the robot, while regulating the rotating speeds of the propellers plays a leading role in the horizontal trajectory manipulation, the deviation between the designated trajectory and the controlled one is acceptable.

Full-order observer-based output regulation for linear heterogeneous multi-agent systems under switching topology

This study addressed the output regulation issue of linear heterogeneous multi-agent systems under switching topology. All agents excluding the external system are divided into two groups with measurable agents or unmeasurable agents. The agents’ states in the first group can be available for measurement while the agents’ states in the second group are unmeasurable. For the second group, a full-order Luenberger observer is devised to recover these agents’ states. Moreover, there are some agents that can not receive the information from the exosystem directly, thus, a dynamic compensator is constructed for these agents. Based on the proposed observer and compensator, a hybrid feedback control strategy is put forward to settle the output regulation issue. Furthermore, the information interaction among agents is expressed by the switching topology, and the topology is assumed to be jointly connected. Finally, two numerical examples are given to illustrate the feasibility of the theoretical results. The results show that whether the states are measurable or not, the proposed control strategy can address the output regulation issue of linear heterogeneous MASs under switching topology. Moreover, the comparative experiment indicates that our method obtains superior performance in terms of convergence speed, and is more efficient in dealing with practical problems.

Hopf Bifurcation and Control of Magnetic Bearing System with Uncertain Parameter

In this paper, the Hopf bifurcation and control of the magnetic bearing system under an uncertain parameter are investigated. Firstly, the two‐degree‐of‐freedom magnetic bearing system model with uncertain parameter is established. The method of orthogonal polynomial approximation is used to obtain the equivalent magnetic bearing model which is deterministic. Secondly, combining mathematical analysis tools and numerical simulations, the Hopf bifurcation of the equivalent model is analyzed. Finally, a hybrid feedback control method (linear feedback control method combined with nonlinear stochastic feedback control method) is introduced to control the Hopf bifurcation behavior of the magnetic bearing system.

Finite-time synchronization of fractional-order complex networks via hybrid feedback control

Abstract This paper addresses the problem with respect to finite-time (FT) synchronization for fractional-order (FO) complex networks. Based on hybrid feedback control technique, Lyapunov approach, and some novel analysis techniques of fractional calculation, some sufficient conditions are obtained to guarantee FT synchronization, and the estimation bound of the setting time for synchronization is given. It is meaningful to find that the setting time is dependent on fractional order, controller parameters and initial value of networks. At last, numerical simulations are presented to illustrate the effectiveness and applicability of our proposed control method and verify our theoretical results.

New Analysis on H∞ Control for Exponential Stability of Artificial Neural Network with Mixed Time-Varying Delays via Hybrid Feedback Control

New Analysis on H∞ Control for Exponential Stability of Artificial Neural Network with Mixed Time-Varying Delays via Hybrid Feedback Control

Stability, bifurcation analysis and chaos control for a predator-prey system

We study qualitative behavior of a modified prey–predator model by introducing density-dependent per capita growth rates and a Holling type II functional response. Positivity of solutions, boundedness and local asymptotic stability of equilibria were investigated for continuous type of the prey–predator system. In order to discuss the rich dynamics of the proposed model, a piecewise constant argument was implemented to obtain a discrete counterpart of the continuous system. Moreover, in the case of a discrete-time prey–predator model, the boundedness of solutions and local asymptotic stability of equilibria were investigated. With the help of the center manifold theorem and bifurcation theory, we investigated whether a discrete-time model undergoes period-doubling and Neimark–Sacker bifurcation at its positive steady-state. Finally, two novel generalized hybrid feedback control methods are presented for chaos control under the influence of period-doubling and Neimark–Sacker bifurcations. In order to illustrate the effectiveness of the proposed control strategies, numerical simulations are presented.

Mixed lag synchronization between two complex dynamical networks via hybrid feedback control

Mixed lag synchronization between two complex dynamical networks via hybrid feedback control

О СТАБИЛИЗАЦИИ ДИФФЕРЕНЦИАЛЬНЫХ ГИБРИДНЫХ УПРАВЛЯЕМЫХ СИСТЕМ С ОБРАТНОЙ СВЯЗЬЮ

In this paper two-dimensional systems of differential equations are considered together with their stabilization by a hybrid feedback control. A stabilizing hybrid control for an arbitrary controlled system that belongs to a certain category within two-dimensional systems is constructed as a result of this study and some stabilization proprieties of the system with the obtained hybrid control are presented.

Mixed lag synchronization between two complex dynamical networks via hybrid feedback control

Mixed lag synchronization between two complex dynamical networks via hybrid feedback control

A hybrid feedback control strategy for autonomous waypoint transitioning and loitering of unmanned aerial vehicles

We consider the problem of autonomously controlling a fixed-wing aerial vehicle to visit a neighborhood of a pre-defined waypoint, and when nearby it, loiter around it. To solve this problem, we propose a hybrid feedback control strategy that unites two state-feedback controllers: a transit controller capable of steering or transitioning the vehicle to nearby the waypoint and a loiter controller capable of steering the vehicle about a loitering radius. The aerial vehicle is modeled on a level flight plane with system performance characterized in terms of the aerodynamic, propulsion, and mass properties. Thrust and bank angle are the control inputs. Asymptotic stability properties of the individual control algorithms, which are designed using backstepping, as well as of the closed-loop system, which includes a hybrid algorithm uniting the two controllers, are established. In particular, for this application of hybrid feedback control, Lyapunov functions and hybrid systems theory are employed to establish stability properties of the set of points defining loitering. The analytical results are confirmed numerically by simulations.

Finite-time synchronization of inertial memristive neural networks with time-varying delays via sampled-date control

In this paper, the finite-time synchronization issues for inertial memristive neural networks with time-varying delay using hybrid feedback controller with sampled-date term are investigated. Firstly, by constructing a proper variable substitution,the original system is transformed into the first order differential system. Next, constructing a useful Lyapunov function, a suitable controller and using inequality techniques, some new testable algebraic criterion are obtained for ensuring the finite-time synchronization goal. Moreover, we discussed deeply on the relation between the parameter ξi and estimated value of settling time in the different cases, and we can obtain the minimum estimated value of settling time. Finally, the effectiveness of the theoretical results have been illustrated via two numerical examples.

Improving the performance of semiglobal output controllers for nonlinear systems

For a large class of nonlinear control systems, the main drawback of a semiglobal stabilizing output feedback controllers $(\mathcal{U}_R)_{R>0}$ with increasing regions of attraction $(\Omega_R)_{R>0}$ is that, when the region of attraction $\Omega_R$ is large, the convergence of solutions of the closed-loop system to the origin becomes slow. To improve the performance of a semiglobal controller, we look for a new feedback control law that preserves the semiglobal stability of the nonlinear system under consideration and that is equal to some fast controller $\mathcal{U}_{R_0}$ on a neighborhood of the origin. Under an input-output-to-state stability (IOSS) assumption, we propose a new semiglobal stabilizing hybrid feedback controller that unifies a slow controller that has a large region of attraction with a fast controller having a small region of attraction. This unification is inspired from the elegant hybrid unification of a local controller with a global one given in [21]. Moreover, this unification is different from the recent result [24], since in the cited paper the objective is just the stabilization; whereas in our study, the objective is the stabilization with high performance. Finally, we illustrate our main result by means of two numerical examples.

Parameter identification based on lag synchronization via hybrid feedback control in uncertain drive-response dynamical networks

In this paper, we use a hybrid feedback control method to study lag synchronization in uncertain drive-response dynamical networks with a feature that the unknown system parameter exists in the node dynamics. We then design two hybrid feedback control methods to achieve the lag synchronization including the linear and adaptive feedback control. With the designed controllers and update laws for the system parameter in the node dynamics, we obtain two theorems on the lag synchronization based on the LaSalle invariance principle. When the lag synchronization is achieved, we identify the unknown system parameter. Finally, we provide two numerical examples to verify the efficiency of the proposed control schemes.

Modified Function Projective Synchronization of Complex Networks with Multiple Proportional Delays

This paper deals with the modified function projective synchronization problem for general complex networks with multiple proportional delays. With the existence of multiple proportional delays, an effective hybrid feedback control is designed to attain modified function projective synchronization of networks. Numerical example is provided to show the effectiveness of our result.

Globally Stabilizing a Class of Underactuated Mechanical Systems on the Basis of Finite-Time Stabilizing Observer

Globally exponentially stabilizing a class of underactuated mechanical systems (UMS) with nonaffine nonlinear dynamics is investigated in this paper. The considered UMS has a nonaffine nonlinear subsystem that can be globally asymptotically stabilized by saturated feedbacks, but the saturated feedback cannot be analytically expressed in closed-form. This obstacle limits the real-time applications of most controllers presented in literatures. In this paper, a hybrid feedback strategy is presented to globally exponentially stabilize the UMS with nonaffine and strict-feedback canonical forms. The hybrid feedback strategy is characterized by the composition of partial states feedback and partial virtual outputs feedback based on a higher-order finite-time stabilizing observer. The presented hybrid feedback controller can be synthesized by applying Lyapunov stability theory. Some numerical simulations associated with two underactuated nonlinear systems, the Acrobot system and the Inertia-Wheel-Pendulum (IWP) system, are employed to demonstrate the effectiveness of the proposed controller. The presented control strategy can be applied in real time, thus providing a new feasible dynamic model other than the differential flatness systems for synthesizing the mechanical systems of general underactuated legged robots.

Hybrid Generalized Function Projective Delay Synchronizationin Uncertain Complex Dynamical Networks with Time Delay and Disturbance via Hybrid Feedback Control

Hybrid Generalized Function Projective Delay Synchronizationin Uncertain Complex Dynamical Networks with Time Delay and Disturbance via Hybrid Feedback Control

A Fully Integrated Reconfigurable Switched-Capacitor DC-DC Converter With Four Stacked Output Channels for Voltage Stacking Applications

This work presents a fully integrated 4-to-1 DC-DC symmetric ladder switched-capacitor converter (SLSCC) for voltage stacking applications. The SLSCC absorbs inter-layer load power mismatch to provide minimum voltage guarantees for the internal rails of a multicore system that implements four-way voltage stacking. A new hybrid feedback control scheme reduces the voltage ripple across stacked voltage layers for high levels of current mismatch, a condition that exacerbates voltage noise in conventional SC converters. Furthermore, the proposed SLSCC dynamically allocates valuable flying capacitor resources according to different load conditions, which improves conversion efficiency and supports more power mismatch between the layers. Implemented in TSMC’s 40G process, the SLSCC converts a 3.6 V input voltage down to four stacked output voltage layers, each nominally at 900 mV.